The high temperature reformer technology began when the German chemist Lurgi suggested a coal-gas reaction(C+H2O→CO+H2). Before the present applicant disclosed the patented high temperature reformer (patent documents 1 through 7), the coal-gas reaction was limited to coal gasification; ground coal is combusted with oxygen gas in order to bring up the reactor temperature, and then hot steam is injected into the coal furnace. This method of coal gasification is known as the partial oxidation method, and the resulting reaction temperature runs just around 1,000° C., and a mixture of hydrocarbons are generated. However syngas(CO+H2) after extensive gas separation amounts to about 5% of total gas mixture produced. Furthermore, the temperature of the reforming furnace could not be maintained at 1200° C. or higher by burning coal. Currently, it is known that only the SASOL company of South Africa maintains an economical syngas production.
At the end of the last century, the present applicant reexamined the Lurgi coal-gas reaction. The results of the experiment (see non-patent document 1) were significantly different from the facts which were widely known at the time. The results of the experiment were as in the following. 1) The temperature at which all carbon reformed without catalyst to carbon monoxide gas and all hydrogen atom reduced into H2 gas was just above 1200° C.; 2) Not only carbon of coal, but of all carbonaceous substance reformed into carbon monoxide (CO) at 1200° C. or higher; 3) At the temperature above 1200° C., all hydrocarbons including methane disappeared quickly, and all other hydrocarbons were not detected by a gas detector. The only detected carbon species were CO and CO2. Since the gas generated at a temperature of 1200° C. or higher did not contain any carbon species except for CO gas, unlike in a conventional gasification method, it was not necessary to carry out the gas separation process. The present applicant conducted additional experiments with great interest in the results of 2). The experiments were conducted on a waste tire, crude rubber, synthetic resin and biomass, and only biomass had a problem. The reason for this is that biomass contains a large amount of moisture, and thus the region near the carbons of biomass could not be heated to a temperature of 1200° C. within a short period of time. In particular, the carbon reforming reaction was an endothermic reaction, and a heat of 1200° C. required for the reforming reaction was not supplied to the carbons.
When the present applicant became aware that the Lurgi coal-gas reaction reached the thermal equilibrium at 1200° C., the present applicant constructed a reforming furnace capable of maintaining a temperature of 1200° C., i.e., the most efficient condition for the reaction. The reforming furnace was named Kim reformer (see patent document 1), and was constructed for experimental purposes.
However, the Kim reformer merely produces syngas at a capacity of 100 m3/hour, and has a problem in that 30% of generated syngas has to be burnt and used as heat source for the purpose of the continuous operation thereof. In other words, for the Kim reformer to be widely used for industrial purposes, the reformer can be said to be economic only when the reformer can produce syngas at a capacity of 500 m3/hour or more.